Harvard has looked at the data and two studies have reached an unavoidable conclusion: Self-absorbed loudmouth guys have overrun Twitter like no other place on the internet. You probably figured. But now there are numbers.

Harvard Business Review has found, "The top 10% of prolific Twitter users accounted for over 90% of tweets. On a typical online social network, the top 10% of users account for 30% of all production." And a separate study shows that Twitter's about the only social network where men are more likely to be "followed" by both other men and by women. That's in contrast to other social networks, where "most of the activity is focused around women."

Even Wikipedia, notorious for being run by a tiny, self-obsessed cabal, is not so bad: There, 90 percent of the content comes from the most active 15 percent of users.

Such asymmetry, of course, is baked right into Twitter's architecture. The microblogging service grew quickly because it allows one-way "follows." On Facebook, in contrast, accounts can only be linked with the permission of both parties.

If it's any consolation, relentless self-promotion is a necessary but not sufficient condition of popularity on Twitter. Have a look at Twitter's most prolific authors — have you heard of a single one? But good luck becoming one of the most influential tweeters if you don't constantly churn out copy.